1. Field of the Invention
The invention relates to a piston-cylinder assembly having a speed-dependent damping force and including a piston rod axially movable in a cylinder and a piston dividing the cylinder into two working spaces connected by a flow passage which can be closed by a valve body in response to dynamic pressure.
2. Description of the Related Art
DE 198 01 722 discloses a piston-cylinder assembly having a speed-dependent damping force, which assembly has a positionally fixed intermediate washer in which a valve closing as a function of speed is arranged. The valve comprises a valve body having a conical valve surface, the valve body being prestressed in the opening direction by a conical coil spring. This construction has the disadvantage that because of the positionally fixed intermediate washer, there is a stroke loss of the order of magnitude of the axial extent of the working space between the intermediate washer and the separating piston.
DE-C 545 334 describes a hydraulic brake, comprising a piston rod which is guided in an axially movable manner within a cylinder filled with a damping medium, a piston being arranged on the piston rod, which piston divides the cylinder into a working space on the piston-rod side and a working space remote from the piston rod, the two working spaces being connected to each other by at least one flow passage which is activated as a function of the axial position of a valve body, which is prestressed in the opening direction by a spring, the valve body being movable into the closed position as a function of dynamic pressure and at least reducing the passage cross section of the at least one flow passage. The valve body has a planar closing surface which comes to bear on an end surface of the piston. It is not desirable for the piston rod to be blocked, so that any leakage flows between the end surface of the piston and the closing surface of the valve body can be tolerated. There is no reference in this publication to the configuration of a working space.